Page zoom improvements

chrome/browser/ui/browser.cc

Index: chrome/browser/ui/browser.cc
===================================================================
--- chrome/browser/ui/browser.cc	(revision 109526)
+++ chrome/browser/ui/browser.cc	(working copy)
@@ -10,6 +10,7 @@
 #endif  // OS_WIN
 
 #include <algorithm>
+#include <cmath>
 #include <string>
 
 #include "base/base_paths.h"
@@ -153,6 +154,7 @@
 #include "content/public/browser/notification_details.h"
 #include "content/public/common/content_restriction.h"
 #include "content/public/common/content_switches.h"
+#include "content/public/common/page_zoom.h"
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
 #include "grit/locale_settings.h"
@@ -161,6 +163,7 @@
 #include "net/base/net_util.h"
 #include "net/base/registry_controlled_domain.h"
 #include "net/url_request/url_request_context.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
 #include "ui/base/animation/animation.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/point.h"
@@ -1967,16 +1970,71 @@
   if (is_devtools())
     return;
 
-  static const UserMetricsAction kActions[] = {
-    UserMetricsAction("ZoomMinus"),
-    UserMetricsAction("ZoomNormal"),
-    UserMetricsAction("ZoomPlus")
-  };
+  RenderViewHost* host = GetSelectedTabContentsWrapper()->render_view_host();

[James Hawkins, 2011/11/14 18:09:05]

When is |host| NULL?

[csilv, 2011/11/15 02:26:49]

Shouldn't happen, removed.

+  if (!host)
+    return;
 
-  UserMetrics::RecordAction(kActions[zoom - content::PAGE_ZOOM_OUT]);
-  TabContentsWrapper* tab_contents = GetSelectedTabContentsWrapper();
-  RenderViewHost* host = tab_contents->render_view_host();
-  host->Zoom(zoom);
+  if (zoom == content::PAGE_ZOOM_RESET) {
+    host->SetZoomLevel(0);
+    UserMetrics::RecordAction(UserMetricsAction("ZoomNormal"));
+    return;
+  }
+
+  double current_zoom_level = GetSelectedTabContents()->GetZoomLevel();
+  double default_zoom_level =
+      profile_->GetPrefs()->GetDouble(prefs::kDefaultZoomLevel);
+
+  // Generate a vector of zoom level values from an array of known preset
+  // values. The values in content::kPresetZoomFactors will already be in
+  // sorted order.
+  std::vector<double> zoom_levels;
+  bool found_default = false;
+  for (int i = 0; i < content::kPresetZoomFactorsCount; i++) {
+    double zoom_level =
+        WebKit::WebView::zoomFactorToZoomLevel(content::kPresetZoomFactors[i]);
+    if (std::fabs(zoom_level - default_zoom_level) <=
+        content::kPageZoomEpsilon)
+      found_default = true;
+    zoom_levels.push_back(zoom_level);
+  }
+  // If the preset array did not contain the user's default zoom value,
+  // append it to the vector and then sort.
+  if (!found_default) {
+    zoom_levels.push_back(default_zoom_level);
+    std::sort(zoom_levels.begin(), zoom_levels.end());
+  }
+
+  if (zoom == content::PAGE_ZOOM_OUT) {
+    // Iterate through the zoom levels in reverse order to find the next
+    // lower level based on the current zoom level for this page.
+    for (std::vector<double>::reverse_iterator i = zoom_levels.rbegin();
+         i != zoom_levels.rend(); ++i) {
+      double zoom_level = *i;
+      if (std::fabs(zoom_level - current_zoom_level) <=
+          content::kPageZoomEpsilon)
+        continue;
+      if (zoom_level < current_zoom_level) {
+        host->SetZoomLevel(zoom_level);
+        break;
+      }
+    }
+    UserMetrics::RecordAction(UserMetricsAction("ZoomMinus"));

[James Hawkins, 2011/11/14 18:09:05]

For the sake of posterity, it would be interesting to record when the user tries
to zoom minus when already at the lowest (?) level.  Same for zoom plus.

[csilv, 2011/11/15 02:26:49]

Done.

+  } else {
+    // Iterate through the zoom levels in normal order to find the next
+    // higher level based on the current zoom level for this page.
+    for (std::vector<double>::const_iterator i = zoom_levels.begin();
+         i != zoom_levels.end(); ++i) {
+      double zoom_level = *i;
+      if (std::fabs(zoom_level - current_zoom_level) <=
+          content::kPageZoomEpsilon)
+        continue;
+      if (zoom_level > current_zoom_level) {
+        host->SetZoomLevel(zoom_level);
+        break;
+      }
+    }
+    UserMetrics::RecordAction(UserMetricsAction("ZoomPlus"));
+  }
 }
 
 void Browser::FocusToolbar() {